Sandalwood (Japanese name: Byakudan) which has been mainly produced in the eastern district of India has a noble characteristic odor. Therefore, sandalwood has been highly prized as a material for Buddhist statues and various craft carving materials in the Orient. An essential oil obtained from the core and root of the sandalwood by water steam distillation has been used as a perfume from old times. The characteristics of this sandalwood oil reside in that the sandalwood oil shows a soft and sweet woody odor and a balsamic odor, and has high sustainability odor. Therefore, the sandalwood oil has been widely used in oriental-type fragrance, perfume, cosmetics, soap, incense stick and the like (for example, see “Fundamental Knowledge of Perfumes and Flavor Preparation” authored and edited by Mototaka Nakajima, Sangyo-tosyo Kabushiki Kaisya, initial edition third printing (2000), p. 322-323).
However, with increased consciousness on environmental protection, and reinforcement of forest protection as flood control measures in recent years, there is a tendency that excessive felling of natural timber is suppressed. The amount of felling of sandalwood is restricted by the governments in the countries producing it, and deficient supply and cost increase of sandalwood oil has become a problem in the fragrance industry.
For this reason, as a substitute for sandalwood oil, sandalwood-type aroma chemicals such as 2-methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol, 2-ethyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol, 3-methyl-5-(2,2,3-trimethyl-3-cyclopenten-1-yl)-pentan-2-ol, and isocamphylcyclohexanol have been used. However, these sandalwood-type aroma chemicals are deficient in the soft and characteristic sweet odor of natural sandalwood. Therefore, it is difficult to sufficiently reproduce the odor of natural sandalwood.
Generally, as a perfume supplementary to the sweet flavor of a perfume composition, there have been proposed esters, lactones, faranons, vanillins, and the like. Among them, lactones, for example, γ-pentyl-γ-butyrolactone (another name γ-nonalactone) and δ-pentyl-δ-valerolactone (another name δ-decalactone) have coconut-like and milk-like sweetness. Therefore, the lactones exhibit effects of producing food-like sweetness. It is said that γ-ethyl-γ-1-butenyl-δ-valerolactone (for example, see JP-A-Showa-53-84975) is costus-like lactone, and that saturated γ-ethyl-γ-butyl-δ-valerolactone (for example, trade name: COSTAULON manufactured by PFW) is costus-like and woody-like lactone.
In addition, as a lactone compound which can be used as a perfume, 4-cyclohexylpentanolide (for example, see JP-B-Showa-62-5123) and α-alkyl-β-alkyl-δ-alkyl-δ-valerolactone have been known (for example, see U.S. Pat. No. 3,380,457).
As explained above, since many of the above-mentioned lactones have no woody odor, even when the lactones are directly added to sandalwood-type aroma chemicals, the harmony of perfumes are insufficient, and moreover, food-like sweetness impairs the characteristics of the natural sandalwood. In addition, among the lactones, those having a woody odor show a strong costus-like odor, and are insufficient in sweetness. Therefore, even when they are added to sandalwood-type aroma chemicals, sweetness having a natural sandalwood-like sweetness cannot be supplemented. In other words, conventionally, the perfume compositions having a characteristic soft and sweet woody and balsamic odor of natural sandalwood have not yet been artificially obtained.